Pressure ulcers (also known as “bed sores” or “pressure sores”) are typically associated with individuals having compromised mobility or lack of sensation, such as the infirm, elderly and people suffering from stroke, spinal cord injury, bone and joint disease, vascular pathologies, tumours and diabetes. People in intensive care units, hospital wards, or undergoing long surgical procedures are also at risk of developing pressure ulcers.
A pressure ulcer is a tissue abnormality or lesion resulting from pressure imposed upon soft tissue underlying skin, fat, fascia, muscle, bone, or any combination thereof. Following prolonged periods of loading (e.g., compression, tension and shear), the soft tissue positioned between a bony prominence (e.g. the ischial tuberosities, trochanter, shoulder blades, sacrum) and an external surface (e.g. bed, wheelchair) begins to deform and break down. Soft tissue breakdown results from the sustained deformation of tissue and the occlusion of capillaries and ischemic reduction of blood flow (i.e. a reduction of oxygen, nutrients, and removal of metabolic waste products) to the loaded tissue region.
Current techniques employed to prevent pressure ulcer formation include frequent repositioning of the individual, and the use of specialized cushions and mattresses that provide some pressure relief of the tissues at risk. However, effective administration of these pressure-relieving techniques is difficult, expensive and often dependent upon patient compliance. Repositioning of patients must achieve pressure relief to the tissue and must be performed either by hospital staff, caregivers or by encouraging the patient to perform wheelchair push-ups or side-to-side leans. For wheelchair push-ups, the patient has to sustain a push up for at least 1 minute and 53 seconds for the intervention to be effective. This often cannot be done because the patients do not have the arm mobility or strength to perform his maneuver. Specialized wheelchair cushions are commonly used but specialized mattresses are heavy, expensive and not widely utilized. Further, these techniques merely provide passive tissue load reduction, thereby failing to actively engage the patient's own muscles.
Electrical stimulation of muscle tissue, commonly known as electrical muscle stimulation (EMS), has been examined as a means for preventing or mitigating pressure ulcer formation. EMS applied to loaded muscles produces active contraction thereof, dynamically deforms and reshapes the loaded muscle. Reshaping of the mechanically compressed and ischemic muscle reduces tissue injury by redistributing pressure, relieving tissue deformation, restoring blood flow and increasing oxygenation of the target tissue, particularly where the stimulation of the muscle is applied to mimic the natural postural shifts or “fidgeting” of able-bodied individuals.
Currently, in order to achieve accurate and effective electrode placement, EMS electrodes must either be implanted or applied directly on the skin of the patient. However, implanted or direct contact of electrodes with the skin can cause problems. For instance, direct contact can result in irritation of the wearer's skin due to the lack of electrode breathability, the chemical adhesives used, or weakening of the skin with repeated use. Electrode directly applied to the skin can also peel off, rolling up at the edges or bunch up. Where treatment is ongoing, superficial skin injury can occur from continual “ripping off” of the electrodes and hair removal may often be required.
Garments can be configured to administer electrical stimulation without direct electrode-skin interface. For example, garments may have electric coils integrated therein, while others have electrodes removably positioned at pre-determined locations within the garment using snaps or velcro. However, “fixed-placement” garments are limited and electrode positioning is unchangeable from patient to patient.
Some garments, such as that described in United States Patent Application No. US2010/0185259 A1, provide “openings” in the garment (e.g. mesh or netting portions between the electrodes and the person's skin) for securing electrodes, while providing flexibility in electrode positioning. These garments, however, are designed for rehabilitative or exercise purposes (e.g. to contract biceps and quadriceps), that is—to train muscles by taking advantage of the fact that electrical stimulation can be applied to build muscle mass and strength. As such, it is desirable that the openings are operative to provide breathability and to reduce electrode displacement caused when the user becomes sweaty during the workout session.
There is a need for an apparatus and method for use in preventing pressure ulcers in individuals having compromised mobility and/or lack of sensation. Such an apparatus and method may be capable of electrically stimulating pressure-loaded or compressed muscles over long periods of time, without requiring that the electrodes directly adhere to the skin and without causing further mechanical pressure points.